Old Fashioned Chicken Noodle Casserole

INGREDIENTS

3 cups

chopped, cooked chicken

2 cups

dry egg noodles , cooked

2 tbsp

butter

1 cup

chopped onion

1/2 cup

chopped celery

1/4 cup

all-purpose flour

1 1/2 cups

chicken stock or broth

1 1/2 cups

milk

1 tsp

kosher salt

1/4 tsp

white pepper

1/4 tsp

poultry seasoning

1/2 tsp

dried thyme

1/2 lb

fresh mushrooms or equivalent canned, drained mushrooms

1/2 cup

crushed crackers or dried bread crumbs

to 2 tablespoons butter , melted